Renal System

Excretory System main purpose

to maintain homeostasis

what are ways the excretory system works

regulating electrolyte levels in the body

regulating amount of water in body

ridding the body of waste

in humans this involves exchnage material between

the blood and the kidney tubules

How does excretory system work in skin

sweat glands regulate temperature and remove waste by secreting water dissolved salts and nitrogen waste such as urea

Liver

the liver functions in processing waste breaking down toxins and allowing the kidney to get rid of it more safely

what does kidney break down

nitrogen waste into urea

hemoglobin - into bilirubin

Kidney

pair or organs that filter blood to remove waste products

Renal Artery and Vein

Carry blood to away from kidney

Ureter

a duct that serves as an exit for urine producted by the kindey u

urinary bladder

storage resevoir for urine

Urethra

Tube that allows urine to pass outside the body

Renal Cortex

Outermost Reigon of Kidney

contains portion of nephron

Renal Medulla

contains deeper portion of nephron and blood vessels

Renal Pelvis

Where fluid leaving the extercretory tubules is collectted

Nephrons

Nephrons are the functional units of vertebrate kidney

how to nephrons work

they weave back and forth across the renal cortex and medulla

many nephron work in tandem by adjusting blood/urine composition and volume

they regulate absorption and secretion of various substances

Where is glomerulus located

renal Cortex

renal vein

carries blood away from kidney

renal artery

brings blood to the kidney to be filtered

whaat are the 4 key things that take place in the excretory system

filtration, reabsorption, secretion, excretion

Filtration

movement of substances out of the bloodstream into the nephron tubules by being small enough and across filtration membrane

reasorbption

when substance gets pulled out of the tubule and put back into bloodstream

Secretion

when the body moves the substance out of bloodstream into kidney to be excreted without a filtration membrane e

excretion

when things from the kidney tubules to exit the body such as urination

what must the size be for filtration to work

must be small molecules and pass through filtration membrane

what does secretiom allow for

get rid of material of things in excess and maintain homeostasis

Renal Corpuscle is made up of two things

Glomerulus and surrounded by bowman capsule

Renal Tubule

Part of the nephron that leads away from the renal corpsucle and eventually empties into renal pelvis

Glomerulus defintion

a network of capillaries

Afferent arteriole

bring blood to glomerulus

efferent arteriole

takes blood away from glomerulus

Blood pressure forces plasma through small pores

forces into small pores called fenestrations of glomerulus into the next section of the renal corpuscle

Bowman Capsule

Cup Shaped end of the nephron that surrounds glomerulus that allow for things to enter into the tubule

three main things of filtration membrane

glomerulus

the basement membrane

podocytes

what molecules are able to pass through

only allow smaller moleucles and glucose and filtered into kinde u tibiles nut are almost reabsorbed and return to blood

What are the two execptions that can go through filter membrnae but should not and be reabsorbed

glucose and amino acids

Which of the following processes primarily facilitates filtration in the glomerulus?

Hydrostatic Pressure or the pushing blood against the walls of the glomerular capillaries and driving the filtration process.

what substances can pass into the bowman capsule

ubstances like water, electrolytes, glucose, amino acids, and small waste products (urea) can cross the filtration membrane and enter the Bowman’s capsule

Renal Tubule

4 anatomic segements called proximal convoluted tubule, loop of henle (descending and ascending), distal convulated tubulte, and collecting duct

Vasa Recta

network of vessels that surround the renal tubule

Proximal Convoluted tubule

part of the nephron immediately down stream of bowman capsule

what is reasborbed at the proximal convoluted tubule

almost all glucose and amino acids, Na+, Cl-, K-, and HCO4-

What is secreted at the proximal convoluted tubule

drugs and toxias, urea, amonia, hydrogen ions

Net result for filtrate

reduces volume and concentration remains the same

Loop of Henle

a tubule with a descending and asending limb w

what surrounds the loop of henle

surrounded by vasa recta

main function of the loop of henle is

reabsorption of water and salt

Descending loop of henele is permeable to one thing

Water

Descending loop reabsorbs more water through

aquaporins and therefore solute conc increases

Ascending loop of Henle only permeable to

salt

Ascending Loop reabsorbs

salt and conc decrease

Longer loops of henle for orgasnisms means

more opportunity to reabsorb wwater

animals in dry areas have what and why

longer loop of henle to keep water in their body and to retian it more than animals in normal enviorments

vasca recta

capillary network that run alongside the loop of henle and helps return substances back to bloodstream

where does vasa recta work

maintains high salt concentration in medulla

Renal Osmolarity Gradient

the concentration of salt in the tissues of the kdney surroudn the nephron

Renal Osmolarity Gradent increases as we

as we go down from cortex down to outer medulla to inner medulla

Distal Convoluted Tubule

portion of the nephron that helps refine filtrate and empties into the collecting duct wh

what is reabsorbed at the distal convoluted tubule

reabsorbs ions and water and secretes out K+ and H+ and depends on hormone reuglation

Sodium Chloride Cotransporter

Cotransporter is used for reabsorption and moves sodium and chloride out of the kidney tubule and back into blood

Collecting Duct

Final segement of the renal tubules where urine is collected and reabsorbed one more time before it is excreted

what is reabsorbed in collecting duct

reabsorbed is Na+ Cl- water urea and bicarbonate while K+ and H+ is secreated

net result depends on the body

After passing through the nephron the ruine passes to several minor calcyes

minor renal calyces that converge into major calyx

what are the final pathway parts of kidney

the renal pelvis collects thie urine and then exits throguh the ureter

Vasa Recta

is a network of blood vessels that closely surrounds the loop of Henle. It plays a key role in maintaining the osmotic gradient necessary for proper nephron function. If it were damaged, the ability to maintain this gradient would be impaired.

sodium chloride cotransporters

help move sodium and chloride out of the kidney tubule and back into the blood. As the sodium and chloride leave the filtrate, water from the tubules can follow these ions back into the bloodstream to maintain concentration.

Antiduretic Hormone

increases water reabsorption

Aldosterone

increases sodium absorpition to regulate water and salt balance

ADH or antidiuretic hormone

effect on kidney is to retain moire water, and less urine is produced

how does ADH work

it works by inserting aquaporins into the distal convoluted tubule and collecting duct of the nephron which pulls water back into the blood

ADH acts primarily where

on the collecting duct

Collecting duct is usally what

impermeable to water except when ADH is present

Juxtaglomerular Appartus

Special Tissue that consist of cells around the blood supply to the glomerulus

when blood pressure or volume drops what does Juxtaglomerular appartus do

it releases renin which lead to increase in blood pressure or adjust how the kidney respond to maintain homeostasis

Macula Densa

The macula densa is a specialized group of cells in the DCT that monitor sodium chloride concentration in the tubule

how do macula densa and JGA relate

macula densa relays the information to JGA so it can adjust the filtration rate accordingly

Aldosterone

works to icnrease Na+ reabsorption in the distal convoluted tubule and collecting duct

Water passivelt follows sodium where

outo fhte tubule and back into the blood stream

Renin Angiotensis Aldosterone system

Dehydration lead to low blood volume and low blood pressure

JGA notice this low pressure and will release renin

Renin will convert angiotensinogen into angiotensin 1 and then the enztme Angiotensinogen or Ace converting enzyme will make angiotensin1 inton angiotensin 2

this is in the lungs which cause us to be more thirsty , release aldosterone to absorb more water

OVerall this will increase the blood pressure to return back to normal

Diuretics

A substance that when ingestd causes increased amount of fluid loss

diurectics work by

diminishing sodium reabsorption in the nephron meaning less water is reabsorbed and more remains in the kindey

or it can block ADH receptors

where is the JGA kocated

distal convoluted tubule

what does the JGA consist of

juxtaglomerurlar cells and macula densa

what does macula densa cells do

These cells regulate blood pressure by monitoring sodium and chloride concentrations in the filtrate within the kidney tubules.

Aldosterone does what

increases sodium reabsorption in the distal convoluted tubule and the collecting duct. t enters the cells lining the nephron and stimulates the opening of sodium channels, allowing sodium to be reabsorbed into the bloodstream.

what does angiotensin 2 do

increase ADH

Stimulate the Arterties to shirnk and increase blood pressure

increase aldosteroe secretion

secrete thirst

Osmoregulation and Excretion

Process by which animal control solute concentration and balance water intake with water loss

osmoregulation in saltwater fish

water is hypertonic meaning water is constantly lost by osmsois and rarely urinate

what kind concentration is saltwater fish

the urine is very concentrated and little water

Freshwater fish osmoregulation

enviorment is hypotonic and water constantly enters body or their urine is very diluted

Nitrogenous waste disposal

Remaining Nitrogen After Amio acids are metabolized and converted to amonia (NH3)

NH3 is toxic so its converted into urea that our kidney filter out in urine

how do animals get rid of urea

fish - amonia

aninals - urea

reptiles- uric acid

why do fish release amonia

For this reason, only aquatic animals excrete nitrogenous waste in the form of ammonia, as their environment provides abundant water to dilute it safely.

Amonia is toxic and therefore

Ammonia is a toxic byproduct of protein metabolism that requires large amounts of water for dilution during excretion.